2.1 Classification + Biodiversity Flashcards
(61 cards)
What is classification?
Classification is the organisation of living organisms into groups based on accepted principles.
What is phylogenetic classification?
Phylogenetic classification groups organisms based on their evolutionary relatedness. Organisms in the same group have a more recent common ancestor with each other.
All organisms share common ancestors.
What is a branch of evolution?
A branch of evolution is when an organism has a series of mutations that leads to the development of new species.
What is the phylogeny of an organism?
The phylogeny of an organism reflects all the evolutionary branches that led up to its existence.
How can phylogenetic relationships of different species be represented?
Phylogenetic relationships of different species can be represented by a Phylogenetic tree.
Explain what the tips of branches, branch points and trunks represent in a phylogenetic tree.
Living organisms are at the tips of the branches.
Ancestral species are in the branches and trunks.
Common ancestors are found at the branch points
The further up the diagram you go… (Phylogenetic Tree)
The further up the diagram you go, the further forward in time. The species at the top exist now.
Define hierarchy
A hierarchy is a system of ranking in which small groups are nested components of larger groups.
Explain the hierarchical classification system in terms of taxa.
A hierarchical system has been devised for all living organisms. Each grouping in the system is a taxon (plural=taxa). Bigger taxa contain smaller taxa. Within each taxon, organisms are more similar to each other and more closely related than to organisms outside the taxon. Taxa are discrete, an organism belongs in one taxon and in no other.
What is the hierarchy of biological classification?
Domain, Kingdom, Phylum, Class, Order, Family, Genus, Species.
Why do we need a classification system?
A phylogenetic classification system allows us to infer evolutionary relationships. If two organisms are so similar that we put them in the same taxon, we can infer that they are closely related.
Explain why classification systems are “tentative”
The system of classification depends on our current knowledge.
Any system we use is tentative and may be altered as our knowledge advances.
E.g. Analysis of DNA.
What is a domain and how are they defined?
A domain is the largest taxon and all living things belong in one of the three domains.
Domains are defined on the basis of rRNA base sequences and DNA base sequences.
What is the archaea domain?
Archaea means ancient. These are bacteria and often have unusually metabolism. Many are extremophiles which include a lack of molecular oxygen, very high pressure, very high temperatures or a very high/low pH.
Archaea have 70s ribosomes, circular DNA, unusual metabolisms and no membrane bound organelles.
What is the eubacteria domain?
Eubacteria are true bacteria and are prokaryotes, some Eubacteria can also be extremophiles.
Eubacteria have 70s ribosomes, circular DNA and no membrane bound organelles.
What is the eukarya domain?
Eukarya include all eukaryotic organisms, there are four eukaryotic kingdoms : Animalia, Plantae, Fungi and Protoctista.
Eukaryotes have 80s ribosomes, linear DNA is in nucleus and membrane bound organelles.
What is the 3 domain system of classification based on?
The 3 domain system of classification is based on molecular biology techniques, as opposed to observed physical features in the 5 Kingdoms.
What is the 5 Kingdom System used for?
This system places organisms into groups based on their physical appearance and was used before molecular biology techniques were available. All the bacteria from the domains Eubacteria and Archaea are in one kingdom (Prokaryota). The other 4 kingdoms contain the Eukaryotic organisms.
Explain prokaryotes and what they have
Prokaryote : Prokaryota are microscopic.
Prokaryotic, Single-Celled, Mesosome in some, Photosynthetic lamellae in some, 70s ribosomes, peptidoglycan cell wall, saprotrophic, parasitic or autotrophic,
What do animalia have?
Eukaryotic, Multicellular, Nucleus, Mitochondria, 80s ribosomes, ER, small scattered and temporary vacuole, Heterotrophic, Nervous Coordination.
Explain protoctista and what they have
(Some are more plant-like/animal-like) : The outliers.
Eukaryotic, Single-Celled or Multicellular, Nucleus, Mitochondria, Some have chloroplasts, 80s Ribosomes, ER, some have vacuoles, Some have a cellulose cell wall, Some autotrophic/heterotrophic.
Explain Plantae and what they have
(Flowering/Non-flowering) : Mosses, horsetails and ferns reproduce with spores whilst conifers and flowering plants reproduce with seeds.
Eukaryotic, Multicellular, Nucleus, Mitochondria, Chloroplasts, 80s Ribosomes, ER, Large central permanent vacuole, Cellulose cell wall, Autotrophic.
Explain fungi and what they have
Yeasts are single-celled.
Eukaryotic, Single-celled/hyphal, Nucleus, Mitochondria, 80s Ribosomes, ER, Large central permanent vacuole, Chitin cell wall, Saprotrophic/parasitic.
What’s classification used for?
Classification is a human concept developed for convenience and allows us to infer evolutionary relationships. If a new organism is discovered, then we can use its characteristics to predict some of its other characteristics. It also makes communication easier.
